N-substituted sulfamoyl compounds useful as herbicides

ABSTRACT

Substituted N-sulfamoyl pyridine compounds are useful in the destruction and prevention of weeds and unwanted plants.

[451 Jan. 9, 1973 [541 N-sUas'i iT n SULFAMOYL COMPQUNDS USEFUL AS HERBICIDES [75] Inventor: William J. ll oulllian, Mountain Lakes, NJ.

[73] Assignee: Saiidoz-Wander,lnc.,Hanover,N.J. 22 Filed:

June 25, 1969 211 Appl. No.: 836,629

[52] US. Cl. ..71/94, 71/84, 71/92,

[51] lnt.Cl. ..A01n9/22 [58] Fieldofsearch .Q ..71/92,103

Primary Examiner-James 0. Thomas, Jr. Attorney-Gerald D. Sharkin, Frederick H. Weinfeldt, Robert S. Honor, Walter F. Jewell and Richard E. Vila 57] ABSTRACT Substituted Nsu1famoyl pyridine compounds are useful in the destruction and prevention of weeds and unwanted plants.

7 Claims, No Drawings N-SUBSTITUTED SULFAMOYL COMPOUNDS USEFUL AS HERBICIDES The invention relates to N-sulfamoyl compounds which possess post and pre-emergent herbicidal activity. The invention relates in particular to N-sulfamoyl compounds having herbicidal activity in which the nitrogen atom is a member of a heterocyclic ring or is attached directly to an organic ring.

The herbicidally active sulfamoyl compounds contemplated by the present invention are selected from compounds having the structure:

where R and R are hydrogen or a lower alkyl, i.c., containing one to four carbon atoms such as methyl, and A is a nitrogen containing moiety selected from:

where n is 4 to 12, preferably 4 to 8; ii. a piperidino radical of the formula A Row where R, R R R and R represent hydrogen, lower alkyl containing one to four carbon atoms, and phenyl, provided at least three of the R, R, R R and R are hydrogen and provided also that at least one of R, R, R R and R is other than hydrogen;

iii. a 4-phenyl-l ,2,5,6-tetrahydropyridino radical having the structure iv. a piperazino radical of the formula 5 where R represents hydrogen or lower alkyl having one to four carbon atoms and R represents cyclohexyl, l,2,3,4-tetrahydro-l-naphthyl, l-indanyl or Z-indanyl.

The compounds of formula I in which the A" is a piperazino radical form acid addition salts having the same order of activity as the base. Representative of such salts are the mineral acid salts, such as the hydrochloride, hydrobromide, sulfate, phosphate and the like and the organic acid salts, such as the succinate, benzoate, acetate, p-toluenesulfonate, benzene sulfonate and the like. The salts are readily prepared by reacting the base with the appropriate acid.

An additional aspect of this invention concerns compounds of formula I which are new. These have the structure where A is:

and its acid addition salts described above,

and its acid addition salts where R represents a lower alkyl containing one to four carbon atoms, phenyl, chlorophenyl, methoxyphenyl, benzyl or chlorobenzyl;

v. a l,2,3,4-tetrahydro isoquinolino radical having the structure where R is hydrogen or benzyl; and vi. a group having the structure where A has the significance previously indicated.

Compound la is prepared by treating the amine, A- H, with sulfamide. While solvent and reaction conditions are not critical the reaction is generally carried out in an inert solvent (one which reacts with none of the reactants under the condition of the reaction) such as water, ethanol, or a tertiary amine at temperatures between about 50 and 250 C. The preferred temperature range is about 55 C. to about 125 C., and ordinarily the reaction is carried out at the reflux temperature of the system. Although stirring is preferred, it is not required. The reaction, generally, will proceed to completion in from about 1 to 5 hours.

To prepare a compound lb in which either R or R is other than hydrogen, the previously described amine A-H is treated with a mono or di-lower alkyl sulfamoyl chloride, compound IV. The reaction involved is shown in the following scheme:

iii u NSOzCl A-H ASzN\ 24 R IV II lb where R" represents lower alkyl having one to four carbon atoms and R is hydrogen or lower alkyl having one to four carbon atoms. The reaction is carried out over a period of l to 5 hours preferably at a temperature between -l 0 and C. An inert solvent, i.e., one which does not react with either of the reactants, such as pentane, hexane, heptane, benzene, diethyl ether, dioxane or one of the tertiary amines previously mentioned, is normally employed in the reaction.

In many instances, the mono or di-lower alkyl sulfamoyl compound IV is available commercially. They can also be prepared by treating an amine Ila having the structure:

where R" represents lower alkyl having one to four carbon atoms and R is either hydrogen or a lower alkyl having one to four carbon atoms, with sulfuryl chloride at a low temperature, e.g., within the range of about 50 to 0 C. The reaction involved is:

This reaction is normally carried out in an inert solvent, i.e., one which does not react with the reactants under the conditions contemplated such as a tertiary amine solvent, e.g., triethylamine or pyridine.

The produce Ia or lb in the above processes can be isolated using known techniques, e.g., evaporating off the solvent and recrystallizing the crude product thus obtained from methanol-water to obtain the purified product.

Some of the preferred nitrogen-containing groups corresponding to A are as follows: pyrrolidino, hexamethylenimino, heptamethylenimino, octamethylenimino, dodecamethylenimino, piperidino, 4-

piperidino, 2-methyl-S-ethylpiperidino, 4-n-propylpiperidino, N-phenylpiperazino, N-o-chlorophenylpiperazino, N-o-methoxyphenylpiperazino, N-pchlorobenzylpiperazino, l ,2,3,4tetrahydroisoquino lino, N-methyl-N-cyclohexylamino, l-aminoindanyl, 2- aminoindanyl, l-amino- 1 ,2,3,4-tetrahydronaphthyl and 4-phenyl-l ,2,5,6-tetrahydropyridino.

The present invention is directed particularly to the novel use of the compounds of formula (l), as herbicides. Said compounds may be applied to this use after admixture with a diluent or carrier material or conditioning agent of the kind used or referred to in the art as a pest control adjuvant or modifier. The active agent may then be applied to soil, weeds or unwanted plants by use of conventional applicator equipment. Thus, formulations comprising wettable powders, emulsifiable concentrates or granules may be prepared, admixed with the appropriate diluents or carriers, and applied to provide the effect desired. The wettable powder may contain about 20-80 percent of active agent, wetting and dispersing agents, and diluent such as finely divided solids, e.g., talcs, natural clays, pyrophyllite,

diatomaceous earth, and flours such as walnut shell, wheat, redwood, soya bean, and cottonseed flours. The emulsifiable concentrate may contain about 25-75 percent of active agent, solvent (water immiscible), and emulsifying agent. The granules may contain about 5-20 percent of the compounds of formula I, carrier, and possibly solvent. Other inert solid carriers which can be used to prepare the herbicidal formulations include magnesium and calcium carbonates, calcium phosphate, sulfur, lime, etc. either in powder or granular form, as may be appropriate. The percentage by weight of the essential active ingredients will vary according to the activity of the compound used and the manner in which the composition is to be applied.

The herbicidal compositions may be applied as a spray or granule to the locus or area to be protected from undesirable plant growth, commonly called weeds, i.e., plants growing there they are not wanted. Such application can be made directly upon the locus or area and the weeds thereon during the period of weed infestation in order to destroy the weeds, or alternatively, the application can be made in advance of an anticipated weed infestation to prevent such-infestation. For example, the compositions can be applied as foliar sprays but can also be applied as sprays directly to the surface of the soil. Alternatively, the dry granular compositions can be applied directly to the plants or the soil.

Depending on the purpose for which the preparation is to be used, it is possible to add other materials having an influence on plant growth, for example, in order to broaden the spectrum of herbicidal activity.

The compounds of formula I may be applied'at a dosage of about 2 to 30 pounds per acre, depending on the herbicidal effect desired and the particular compound used. Generally, when selective herbicidal use is contemplated, the compounds may be used in quantities of about 2-10 pounds per acre. Where non-selective use is desired about 10-20 pounds per acre may be used to provide the desired effect.

The following examples are provided for the purpose of illustration and not by way of limitation. They are not intended so as to limit the scope of the invention as defined in the appended claims.

EXAMPLE I The test tube having a 174 inch hole at the bottom is plugged at the hole with some glass wool. The test tube is filled to about 1% inches from the top with quartz sand which is made inert by washing with acetonedistilled (1:1) water alone and drying. The seed of the plant to be tested is planted in the sand. The tube is fitted with a rubber collar and suspended in an Erlenmeyer flask containing conventional KOPS nutrient solution and the active agent of this invention at a concentration of 50 parts per million (no active agents in the check.) The apparatus is placed under fluorescent lights for about three weeks, and once daily the bottom of the tube is dipped into the solution.

The following results were obtained using cyclic amines having the structure:

where n 4 to 12.

a. N-sulfamoylpyrrolidine of check Test Plant/ Top Root Species Seeds Height Length Comments Field Corn No. 8 3/4 80 73 Extreme wilting,

much necrosis, roots reduced in number Annual Ryegrass 4/4 Sl 49 Necrosis Barnyard Grass '4/4 73 65 Extreme Necrosis Wild Oat 3/4 42 76 Necrosis Johnson grass [/4 82 88 Minor wilting; roots reduced in number Rice 1/4 100 69 Necrosis, very slightly chlorotic; roots reduced in number Soybean Adelphia 2/4 68 14! wilting, minor necrosis; roots reduced in number Coffeeweed 4/4 68 84 Much necrosis, then death; room very slightly discolored Field Bindweed 2/4 55 I03 Normal Redroot Pigwecd 4/8 8 33 No effects, then dcuth', roots somewhat stunted Cocklebur 1/1 90 54 Roots slightly reduced in number and very slightly discolored Cotton (Coker 201 )4/4 92 57 Roots slightly reduced in number, very slightly discolored b. N-dimethylsulfamoylhexamethylenimine lls (tilliln N NU: N

)6 of check Test Plant! Top Root Species Seeds Height Length Comments Annual 4/4 35 54 Much necrosis Ryegrass Soybean 4/4 59 74 Necrosis and (Adelphia) epinasty,

roots slightly stunted c. N-sulfamoylheptamethyleneimine (C D1 N- S OzNHg of check Test Plant/ Top Root Species Seeds Height Length Comments Annual 3/4 33 68 Necrosis Ryegrass Barnyard 3/4 9] 70 Necrosis Grass Wild Oat 1/4 36 95 Necrosis Soybean 2/4 92 59 Much necrosis, Adelphia epinasty,

slight sparseness of roots Coffee 3/4 46 68 Extreme necrosis weed Field 4/4 58 93 Necrosis Bindweed Redroot 6/8 50 Necrosis Pigweed d. N-sulfamoyloctamethylenimine (U n D8 N S OzNHz of check Test Plant/ Top Root Species Seeds Height Length Comments Annual 3/4 23 43 Extreme necrosis Rycgrass Barnyard 3/4 82 78 Much necrosis Grass Wild Oat 4/4 40 95 Necrosis Soybean 3/4 50 44 Much necrosis, Adelphia epinasty, slight sparseness of roots Coffee- 3/4 60 58 Extreme necrosis weed Velvet 4/4 67 6] Much necrosis, roots stunted Leaf Cotton 1/4 96 54 Minor necrosis, slight epinasty, much stunting of roots Cokcr ZOI e. N-sulfamoyldodecamethylenimine i (0112) N-S OQNHQ of check Test Plant/ Top Root Species Seeds Height Length Comments Field 4/4 91 53 Extreme necrosis,

minor wilting, roots stunted, sparse and very slightly discolored Annual Ryegrass Barnyard Grass Wild Oat Johnsongrass Very slight necrosis;

roots stunted and sparse Chlorosis and very slight necrosis, then death; roots sparse and very stunted Much stunting of roots Extreme necrosis;

very much stunting of roots Using the procedure outlined in the preceding exama. N-sulfamoylpiperidine Test Species Field Corn No. 8 Annual Ryegrass Barnyard Grass Dawn Rice Coffee- I weed Redroot Pigweed 4 Cotton Coker 20l Plant/ Seeds /4 Comments Extreme wilting,

much necrosis, roots much reduced in number Necrosis Extreme necrosis and minor chlorosis,

then death Necrosis, roots somewhat stunted Necrosis and chlorosis Necrosis Roots very slightly reduced in number This compound shows some selectivity for cotton.

b. 4-Methyl-N-sulfamoylpiperidine Test Species Plant/ Seeds of Check Top Height Root Length Comments pie, the following results were obtained with compounds having the structure Barnyard 4/4 77 61 Extreme necrosis, Grass then death; roots very slightly stunted Redroot 5/8 8 33 Chlorosis and Pigweed extreme cpinusty,

then death; mots stunted c. 2,5-dirnethyl-N-sulfamoylpiperidine CHa s 0mm of Check Test Plant] Top Root Species Seeds Height Length Comments Annual 4/4 25 22 Necrosis and death, Ryegrass, sparseness and slight discolorin g of the roots Coffee- 3/4 32 42 Extreme necrosis and weed death; roots sparse Redroot 4/8 l7 l7 Auxis effect and Pigweed death Velvet 4/4 27 44 Necrosis and death Leaf d. 3,4-Dimethyl-N-sulfamoylpiperidine -wCHa S OzNHz of Check Test Plant/ Top Root I Species Seeds Height Length Comments Annual 2/4 28 32 Considerable Ryegrass chlorosis and necrosis; minor sparseness of roots Barnyard 3/4 82 35 Necrosis and death; Grass slight discoloration of roots Wild 3/4 40 67 Chlorosis and considerable necrosis; minor sparseness of roots .lohnson- 2/6 41 I9 Necrosis and death; 8 minor discoloration of roots Soybean 3/4 73 83 Considerable Adelphia necrosis; minor discoloration of roots Colfee- 4/4 57 63 Necrosis and death; weed minor sparseness of roots Field 3/4 30 20 Necrosis and death Bindweed Redroot l/8 i7 Extreme auxin effect Pigweed and death Velvet 3/4 40 Extreme necrosis and death Leaf e. 3,5-Dimethyl-N-sulfamoylpiperidine Test Plant/ Species Seeds Field 4/4 No. 8

Annual 4/4 Ryegrass Barnyard 4/4 Crass Wild 4/4 ()at Soybean 4/4 Adelphia CnlTee- 4/4 weed i S OzNHz of Check Top Root Height Length 123 47 f. 3-Ethyl-N-sulfamoylpiperidine Plant/ Test Species Seeds Annual 4/4 R yegrass Barnyard 4/4 Grass Wild I 4 Oat C offcc 4/4 weed Field 3/4 Bindweed Redroot 2/ 8 Pigwecd Velvet 3/4 Leaf CzHs S OzNHt of Check Top Root Height Length 42 i6 Comments Much necrosis Much necrosis Epinasty, then death;

roots somewhat stunted Much necrosis; mots somewhat stunted Extreme necrosis and much epinasty Necrosis and much epinasty than death Comments Considerable Chlorosis Extreme necrosis and death Extreme chlorosis Auxin effect, necrosis and death; minor sparseness of roots Necrosis and death;

sparseness of roots Auxin effect and death Extreme necrosis and death; spuresencss of roots g. 2Methyl-S-ethyl-N-sulfamoylpiperidine Test Plant Species Seeds Field Corn 4/4 of Check Top Height Root Length 47 Comments Much necrosis, much wilting; roots very discolored Annual 4/4 Ryegrass Soybean 3/4 Adelphia Coffce- 4/4 weed Velvet 1/4 Leaf Cotton 2/4 Coker 20l Necrosis; mots very slightly stunted Epinasty and much necrosis, roots somewhat sparse and very slightly discolored Much necrosis, then death Epinasty, then death;

roots extremely stunted Minor necrosis; roots very discolored h. 4-(n-propyl)-N-sulfamoylpiperidine Test Plant/ Species Seeds Field Corn 3/4 No. 8

Annual 4/4 Ryegrass Barnyard 4/4 Grass Wild 2/4 oat Johnson- 1/6 grass Wheat 4/4 Red Coat Redroot 6/8 Pigweed Cotton 1/4 (taker 20l Comments Extreme necrosis;

roots very stunted, somewhat sparse and very discolored Minor necrosis Very slight necrosis,

then death; roots discolored and very stunted Very slight necrosis; roots very stunted Extreme epinasty,

then death; roots extremely stunted Very slight epinasty Extreme epinasty,

then death; roots somewhat stunted Minor necrosis; roots very discolored This compound showed some specificity towards wheat and cotton.

i. N-dimethylsulfamoylpiperidine Test Plant/ Species Seeds Annual 3/4 Ryegrass" Barnyard 2/4 Grass of C heck Top Root Height Length Comments Necrosis, slight stunting of roots Early death, much stunting of roots Cocklebur" l/l Cotton 2/4 Coker 20l Slight chlorosis; slight root discoloration Root discoloration )The results shown were obtained at a dosage level of 10 parts per million.

EXAMPLE 3 Using the procedure of Example 1, the following results were obtained with piperazines having the structure where R is as indicated previously.

a. N-sulfamoyl-N'-phenylpiperazine TBS! Plant/ pecies Seeds Qarnyard 2/4 Grass Anriual 4/4 Rycgrass L r 1/8 C rabgrass Qofiee 3/4 Weed Field 7 3 4 Bindweed The above results were obtained at a dosage level of of check Top Height 16.8

100 parts per million.

b. N-sulfamoyl-N-(o-chlorophenyl)piperazine Root Length 50.0

Comments Leaves extremely necrotic, roots sparse; death Leaves extremely necrotic and epinastic; roots slightly reduced Necrosis and death;

roots discolored and Sparse Stern and leaves epinastic; roots unbranched, discolored Much chlorosis and cpinasty, roots unbranched Much necrosis; roots discolored stunted and very slightly discolored Barnyard 3/4 68 52 Necrosis, then death; Grass roots very stunted 4/4 26 48 Necrosis, roots sparse Oat and extremely stunted 5 n- 2/4 0.44 31 Extreme necrosis, grass then early death;

roots sparse and extremely stunted wltttl. 4/4 77 75 Very slight necrosis, Red Coat very slight wilting;

minor stunting of roots Soybean 4/4 35 47 Minor necrotic Adclphia spotting; roots very stunted; branch roots sparse, minor discoloration Coffee- 4/4 40 79 Germination weed interrupted by death; roots sparse and stunted V EiQltL 4/4 40 40 Stunting of upper Bindweed plant parts; root system extremely stunted and lacking all branch roots Cetton 4/4 83 79 Somewhat epinastic Coker 201 growth; roots discolored, stunted, branch roots sparse.

The results of these tests indicate that this compound has some selectivity favoring wheat and cotton.

c. N-sulfamoyl-N-(o-methoxyphenyl)piperazine one.

N N-SOQNHZ of check Test Plant/ Top Root Species Seeds Height Length Comments Barnyard 4/4 75 52 Much necrosis, minor rass discoloration of roots Wild 3/4 40 76 Necrosis Oat Coffee- 3/4 40 32 Slight necrosis, then weed death, roots discolored with minor sparsencss Cotton 1/4 69 29 Sligh necrosis, roots COkfil 20! Hunted d. N-sulfamoyl-N'-(p-chlorobenzyl)piperazine CHN N-S 0mm Test Plant} Top Root Species Seeds Height Length Comments Annyaj 4/4 28 30 Extreme necrosis in R yegrass leaves and strong auxin effect, extreme in roots Barnyard Grass Coffeeweed Extreme necrosis and death; auxin effect considerable in roots Extreme auxin effect necrosis death; auxin effect high in roots Employing the procedure outlined in Example 1, the following results were obtained with N-sulfamoyll,2,3,4 tetrahydroisoquinoline.

Test Species Annual Ryegrass Johnsongrass Wheat Red Coat Soy bean? Adelphia I Coffeeweed Field Bindweed itedrd t Pigweed Velvet Leaf Cotton Coker 201 This compound demonstrated some selectivity in favor of cotton.

% of check Plant/ Top Root Seeds Height Length 4/4 23 28 EXAMPLE Comments Extreme necrosis and extreme epinasty; roots stunted Much necrosis Extreme necrosis and extreme epinasty; roots with minor stunting Extreme epinasty and much necrosis, then death; roots greatly stunted Much epinasty, then death; roots sparse, stunted, and discolored Extreme necrosis and extreme epinasty Minor necrosis and minor epinasty, roots very stunted Extreme necrosis,

then death; roots with minor stunting Very slight spinasty, roots somewhat sparse.

where R' and R" are as shown.

a. N-methyl-N-sulfamoylcyclohexylamine Test Species Field. Corn No. 8

Annual Ryegrass Barnyard Grass Wild oat Dawn Rice Soybean Adelphia Coffeeweed Eield Bindweed Redroot Pigweed Coeklebur Cotton Coker 201 Plant/ Seeds 4/4 of check Top Height Root Length 5 3 b. l-sulfamoylaminoindane Comments Extreme necrosis;

roots discolored and greatly reduced in number Much necrosis; roots very slightly discolored Extreme necrosis, much chlorosis; death of two out of three Extreme necrosis,

followed by death; roots extremely stunted Early death, roots extremely stunted and extremely reduced in number Extreme necrosis;

roots very slightly reduced in number Necrosis, then death;

branch roots reduced in number Minor necrosis; roots epinastic, lacking in all branch roots Extreme stunting,

then death; minor stunting of roots Necrosis, minor epinasty; number of branch roots much reduced Roots stunted and discolored Test Species Field Corn No. 8

Coffeeweed Field Blndweed Plant/ Seeds /4 Height 91 Root Length 37 Comments Considerable necrosis of leaves, roots extremely discolored Considerable necrosis and death; auxin effect in both leaves and roots Considerable necrosis in leaves; extreme auxin effect in both leaves and roots.

4-phcny1-1,2,5,6

tetrahydropyridine extremely stunted N-su1famoyl-4-phenyl-1,2,5 ,6-

tetrahydropyridine EXAMPLE 8 N-dimethylsulfamoyl-N-methy1piperazine 7 In a suitable flask, 0.1 moles of N-methyl-piperazine is admixed with 0.1 l moles of dimethylsulfamoyl chloride in 150 parts by volume of dry diethyl-ether. The reaction mixture is maintained at a temperature I between =l and 20 C. for a period of 3 hours. The solvents are evaporated off and the product is recrystallized from 1:1 methanol'water.

Velvet 4/4 47 46 Necrosis, auxin effect Dawn 1/4 60 23 Slight necrosis; roots Le f. and death of Rice extremely stunted leaves; extreme and discolored discoloration auxin '7 effect and Soybean 2/4 108 71 Much necrosis; roots sparseness of roots. Adelphia stunted I 5 Coffee 3/4 72 63 Minor necrosis and QQQQHH 3/4 83 50 Extreme necrosis and weed chlorosis; much Coker 201 auxin effect in stunting and leaves; discoloration of discoloration and roots auxin effect in FOOlS- Field 2/4 45 33 Minor chiorosis;

Bindweed extreme stunting of roots. c. 1,2,3,4-tetrahydro-1-sulfamoylaminonaphthalene couon' 4/4 52 39 Necrosis much Coker 201 discoloration and a W. extreme stunting of H S02 roots N The results with this compound were obtained at a dosage level of 10 parts per million. The compound showed some selectivity for corn.

EXAMPLE 7 of check N-su1famoy1-N-pheny1piperazine Test Plant Top Root Species Seeds Height Length Comments I in a suitable flask equipped with a stirrer and a con- Field Com 4/4 105 ecmsls denser attached to a bubble detector, 1.0 moles of N- gg i 3/4 40 20 h ncCmSisJhen phenylpiperazine and 1.] moles of sulfamide are discats early death; much solved in 750 ml. of pyridine. The solution is refluxed i and stirred until gassing is no longer detected in the WildOat 3/4 28 33 Much necrosis; roots bubble detector. The solvent (pyridine) is removed in stunted Wham 4/4 80 106 Minor necrosis; vacuo on a rotary evaporator. The crude product is weed min'or sparseness of recrystallized from methanol/water yielding the product, N-sulfamoyl-N'-phenylpiperazine, m.p. O O Cofiee- 3/4 55 74 Extreme necrosis, 174 C.

weed t death Using similar procedures and refluxing N-sulfamide flag 1/4 20 24 Much epinasty men 35 with the amine indicated in the following table the seaweed" death; extreme products shown are obtained.

' stunting of roots Bpd qt 5/8 25 72 Extreme chlorosis, Pi weed then early death; Melting minor stunting of Amine Product Point "C roots N-( o-chlorophenyl 40 piperazine N-sulfamoyl N'-(olbl l 48 I5 e si deaihchlorophenyl)piperazine 1 1 1-1 12 Leaf Extreme stunting of N-(mmethoxy) piperazine N-sulfamoyl-N'-(o- 'methoxyphenybpiperazine 53455 Cotton 3/4 83 72 Much necrosis, minor MmetMlPiPemzine 127 Coker 201 I stunting and a 7....

discoloration of I roots hydroisoqumoline N-su1famoy1-l,2,3,4- This compound exhibits some selectivity for corn and l 157-159 l-benzyll ,2,3.4-tetra- Wheat hydroisoquinoline N-sulfamoyl-1-benzy1-1,2,3,4-

' tetrahydroisoquinoline 135-137 EXAMPLE 6 N-methy1cyc1ohexylamine N-methyl-N- Using the procedure described in Example 1, thefolsulfamoylcyclohexylamme 1 i results were obtained with N-sulfamo 1-4- hen- 122's Q y p 1-ammo-1,2,3,4-tetrayl-l ,2 ,5 ,6-tetrahydropyr1dme. hydronaphthalene 1,2,3,4-tetrahydro-1-- sulfamoylaminonaphthalene 99.5-100 l-aminoindane 1 -sulfamoylaminoindane 1 15-1 16 r. 2-aminoindane 2-sulfamoylaminoindane 151-152 What is claimed is:

l. A method for the destruction and prevention of weeds and unwanted plants which comprises applying to a locus to be protected, in amount sufficient to exert a herbicidal action, a compound having the structure:

R "R W where R, R R, R, R R and R each independently represent hydrogen or lower alkyl having one to four carbon atoms provided at least three of R, R", R R and R are hydrogen.

2. The method of claim 1 in which the compound is N-sulfamoylpiperidine.

3. The method of claim l'in which the compound is 3,4-dimethyl-N-sulfamoylpiperidine.

1 NS02N/ 5 R1 where R, R R, R, R, R, and R each independently represent hydrogen or lower alkyl having one to four carbon atoms, provided at least three of R", R", R R and R' are hydrogen. 

2. The method of claim 1 in which the compound is N-sulfamoylpiperidine.
 3. The method of claim 1 in which the compound is 3,4-dimethyl-N-sulfamoylpiperidine.
 4. The method of claim 1 in which the compound is 2-methyl-5-ethyl-N-sulfamoylpiperidine.
 5. The method of claim 1 in which the compound is 4-(n-propyl)-N-sulfamoylpiperidine.
 6. The method of claim 1 in which the compound is 2,5-dimethyl-N-sulfamoylpiperidine.
 7. A composition suitable for the destruction and prevention of weeds and unwanted plants comprising a carrier and in an amount sufficient to exert a herbicidal action, a compound having the structure where R1, R2, R3, R4, R5, R6, and R7 each independently represent hydrogen or lower alkyl having one to four carbon atoms, provided at least three of R3, R4, R5, R6 and R7 are hydrogen. 